Expand: (x+2y+3z)2
We take a=x,b=2y,c=3z in the expansion(a+b+c)2=a2+b2+c2+2ab+2bc+2caWe obtain(x+2y+3z)2=x2+(2y)2+(3z)2+2x(2y)+2(2y)(3z)+2(3z)x=x2+4y2+9z2+4xy+12yz+6zx
Expand (4x−2y−3z)2 using identity
Question 28 Expand the following (i) (4a−b+2c)2 (ii) (3a–5b–c)2 (iii) (−x+2y−3z)2